Merge 3.5 (issue #26923)

diff --cc Misc/NEWS
index e508fc15598b0126f30c89c26498c3efe817f176,48bd626c1d7850de072988d8bca13a140c590303..294956b1d273aa9d6537b4701d3d6d3d27378192
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -16,59 -13,6 +16,63 @@@ Core and Builtin
  - Issue #23782: Fixed possible memory leak in _PyTraceback_Add() and exception
    loss in PyTraceBack_Here().
  
 +- Issue #28471: Fix "Python memory allocator called without holding the GIL"
 +  crash in socket.setblocking.
 +
 +
 +Library
 +-------
 +
 +- Issue #18219: Optimize csv.DictWriter for large number of columns.
 +  Patch by Mariatta Wijaya.
 +
 +- Issue #28448: Fix C implemented asyncio.Future didn't work on Windows.
 +
 +- Issue #28480: Fix error building socket module when multithreading is
 +  disabled.
 +
 +- Issue #24452: Make webbrowser support Chrome on Mac OS X.
 +
 +- Issue #20766: Fix references leaked by pdb in the handling of SIGINT
 +  handlers.
 +
 +- Issue #28492: Fix how StopIteration exception is raised in _asyncio.Future.
 +
 +- Issue #28500: Fix asyncio to handle async gens GC from another thread.
 +
++- Issue #26923: Fix asyncio.Gather to refuse being cancelled once all
++  children are done.
++  Patch by Johannes Ebke.
++
 +Build
 +-----
 +
 +- Issue #28208: Update Windows build to use SQLite 3.14.2.0.
 +
 +- Issue #28248: Update Windows build to use OpenSSL 1.0.2j.
 +
 +Tests
 +-----
 +
 +- Issue #26944: Fix test_posix for Android where 'id -G' is entirely wrong or
 +  missing the effective gid.
 +
 +- Issue #28409: regrtest: fix the parser of command line arguments.
 +
 +
 +What's New in Python 3.6.0 beta 2
 +=================================
 +
 +*Release date: 2016-10-10*
 +
 +Core and Builtins
 +-----------------
 +
 +- Issue #28183: Optimize and cleanup dict iteration.
 +
 +- Issue #26081: Added C implementation of asyncio.Future.
 +  Original patch by Yury Selivanov.
 +
  - Issue #28379: Added sanity checks and tests for PyUnicode_CopyCharacters().
    Patch by Xiang Zhang.